Grapples for lifting logs and similar elements are well known and generally comprise a boom mounted on a suitable transportation vehicle with a swivel coupling at the end of the boom which carries a mounting head for swivelling movement around a vertical axis at the end of the boom. On the mounting head is carried a pair of upstanding parallel plates each on a respective side of the swivel and between the plates is a pair of grapple jaws with each jaw having a pivot mounting at its upper inner end. The jaws are driven by suitable hydraulic mechanisms so that depending outer end can be moved inwardly and outwardly to engage around a collection of logs or other equipment to be lifted.
The grapple is often used in logging for lifting logs onto a trailer for transportation and generally the logs are of the same or similar length with the intention that they be loaded in parallel arrangement with the ends at the sides of the trailer.
Various techniques are used for locating the ends so that they are substantially coplanar standing in vertical planes at the side of the vehicle. Some logs are difficult to load in this way and that they are particularly slippery and tend to twist within the grapple jaws and poplar is one example of logs which are difficult to load in this way.